Photovoltaic Surface Treatment for Interface Cohesion
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Solution Overview
Problem
Photovoltaic cells face limitations in achieving grid parity due to high surface state density causing strong surface Fermi level pinning, which reduces open circuit voltage and fill factor, hindering efficiency improvements.
Innovation Solution
A surface treatment process involving hydrogen fluoride cleaning, ammonium sulfide passivation, and plasma surface treatment is applied to the absorber layer, reducing surface state density and enhancing the interface cohesion, thereby increasing open circuit voltage and fill factor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If surface treatment is applied to reduce surface state density, then open circuit voltage and fill factor improve, but device complexity and manufacturing process complexity increase
Solution Approach 1:
The patent applies preliminary surface treatment actions (hydrogen fluoride cleaning, ammonium sulfide passivation, plasma treatment) to the absorber layer before final device assembly. These preliminary actions reduce surface state density and improve interface quality, thereby enhancing open circuit voltage and fill factor without requiring complex modifications during later manufacturing stages.
Solution Approach 2:
The patent introduces intermediate surface treatment layers and processes (ammonium sulfide passivation layer, plasma-treated surface layer) that act as mediators between the absorber layer and subsequent layers. These intermediary layers reduce surface recombination velocity and improve interface cohesion, resolving the contradiction by adding controlled complexity at the surface level to achieve improved device performance.
2Productivity
If multiple surface treatment processes are applied to improve interface cohesion, then energy conversion efficiency increases, but manufacturing time and process steps increase
Solution Approach 1:
The patent combines multiple surface treatment processes (hydrogen fluoride cleaning, ammonium sulfide passivation, plasma treatment) into a integrated surface treatment sequence applied to the absorber layer. By merging these processes in a coordinated manner, the patent achieves improved interface cohesion and energy conversion efficiency while minimizing the total manufacturing time through process optimization and integration.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The surface treatment significantly improves open circuit voltage, fill factor, and energy conversion efficiency by reducing surface recombination velocity and forming a more cohesive interface, potentially achieving performance comparable to conventional solar cells.
Implementation Method 1
performing a hydrogen fluoride cleaning process on the surface of the absorber layer
Implementation Method 2
performing an ammonium sulfide passivation process on the surface of the absorber layer
Implementation Method 3
performing a plasma surface treatment on the surface of the absorber layer, exposing the surface of the absorber layer to a plasma, wherein the plasma transforms into a solid state forming a thin solid layer on the surface of the absorber layer
Data Source
AI summary
The present invention relates generally to semiconductor devices and more particularly, to a structure and method of forming a photovoltaic cell using a surface treatment to improve device performance. Embodiments of the present invention may improve open circuit voltage, fill factor, and energy conversion efficiency by performing a surface treatment on an upper surface of an absorber layer. The surface treatment may improve device performance by permitting a more cohesive interface between the upper surface of the absorber layer and a lower surface of a passivation layer. The more cohesive interface may allow carriers to move from one layer to another with less resistance, and thus, increase device performance.